The frictional torque generating mechanism for the opening/closing shaft and rotary shaft of a prior art two-shaft hinge comprised, in practically all cases, a mechanism in which a plate member was coiled onto a shaft or a mechanism in which rotary frictional torque was generated by a construction in which pressure was applied by a dish spring.
FIG. 16 shows an example of a prior art two-shaft hinge shown in Japanese Patent Publication No. 2002-155923. In this hinge, a plate spring 54 formed in corrugated fashion and brackets 56 are fixed to the shaft at both ends of a press-formed opening/closing shaft 52 by means of a fixing flange 53. Also, a rotary shaft 57 is arranged penetrating to the middle of the opening/closing shaft 52; rotary frictional torque is generated by the method of pressure contact with a plate spring 59.
With the prior art hinge product, due to the fact that no rotary angle stop mechanism of the opening/closing shaft to limit rotation of the rotary shaft was provided and, in addition, due to the method of generating torque by pressing the friction plate into contact using the repulsive force of the dish spring, there were problems of looseness, rattling or poor durability caused by wear of the frictional plates 52, 56 or deformation (weakening) of the plate spring 54. Torque fluctuation or deterioration of durability produced by secular changes not only impairs the quality of the device but may also cause failure. Accordingly, as considered in the above reference, in recent two-shaft hinges, compared with prior art products, closer attention is paid to ease of operation and feeling during opening/closing or rotating, as well as the mechanism for limiting the angle of rotation or opening and closure, and maintenance of a stable torque value, high durability and also a reduction in size and weight are strongly demanded.